Fixes for complex predefined field types (#210)

Updates the protovalidate version to 0.8.2 and fixes three
closely-related bugs:
- `rule` is inadvertently typed incorrectly when it is a repeated rule
field on a repeated field
- `getCELType` inadvertently returns an incorrectly-named message type
when dealing with a message field (using the full name of the field
instead of the full name of the type)
- `getCELType` returns a message type instead of a wrapper type for
wrappers like `google.protobuf.Int32Value`

These bugs are subtle because they don't occur in normal circumstances,
but the new predefined rule tests added in v0.8.2 to close the bugs on
protovalidate-go inadvertently revealed several protovalidate-java bugs.
This validates that more work on the conformance test can still be quite
valuable in finding difficult bugs, even if we don't know exactly what
we're looking for.

Author: jchadwick-buf